643286256 has 120 divisors (see below), whose sum is σ = 1790718720. Its totient is φ = 198921216.

The previous prime is 643286219. The next prime is 643286257. The reversal of 643286256 is 652682346.

It is a happy number.

643286256 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643286257) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1095595 + ... + 1096181.

It is an arithmetic number, because the mean of its divisors is an integer number (14922656).

Almost surely, 2^643286256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643286256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (895359360).

643286256 is an abundant number, since it is smaller than the sum of its proper divisors (1147432464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643286256 is a wasteful number, since it uses less digits than its factorization.

643286256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 711 (or 688 counting only the distinct ones).

The product of its digits is 414720, while the sum is 42.

The square root of 643286256 is about 25363.0884554701. The cubic root of 643286256 is about 863.2463635685.

The spelling of 643286256 in words is "six hundred forty-three million, two hundred eighty-six thousand, two hundred fifty-six".